It is known to use lasers to cut out shapes in clothing material, for making up into particular garments. Laser cutters are popular in this field as they can be used under computer control to give a clear and accurate cut which, in the case of artificial fabrics, will not fray.
In one common type of prior art laser cutter, a sheet of fabric is laid out on a flat cutting table above which a laser is supported in a support frame. The laser in its support frame is movable along two mutually perpendicular axes, and so can be made to describe, and therefore cut, any desired 2-dimensional shape in the material. Once the cutting is completed, the fabric is removed from the cutting table, and taken away for the pieces to be sewn up into a garment.
Such prior art laser cutters suffer from a number of drawbacks. Firstly, the entire laser and collimator apparatus, together with its support frame, must be mounted on tracks above the fabric, and moved around during the cutting process. This apparatus is extremely heavy and unwieldy, and large forces are required to shift it around. To move such a bulky apparatus with the precision required can be very problematic.
Secondly, the fabric must be laid flat on the table, cut, and then removed. This limits the speed of the operation, as the machine cannot be worked continuously, and also places a limitation on the sizes of fabrics which can be cut using the apparatus.
The larger the table, the more difficult it becomes to remove all the pieces of fabric from the table after completion of cutting. The area of the table is generally about 3 m.times.3 m and smaller cut pieces of fabric are easily mislaid during their removal. The sheer size of the apparatus causes other problems. The area that must be made available in a factory for the machine is even larger than the size of the cutting table. This extra space is required by the frame on which the laser is supported. The laser sits firm on its frame, which is moved from side to side and to and fro, to cause the movement of the laser according to a chosen pattern. Space must therefore be provided for the extension of the frame beyond the cutting table, when the laser is positioned close to the edge of this table.
Such prior art laser cutters pose serious health and safety problems. To keep people away from the laser beam during operation of the cutter, access to the cutting table must be prevented. Therefore, guards should ideally be placed around the whole perimeter of this table. However, an even larger area may be hazardous due to the swinging out of the laser frame during operation, as mentioned previously. As soon as the cutting of a particular sheet of fabric has been completed, access is required once more to the cutting table to remove the material. This makes it very difficult to work out and enforce sensible safety regulations.
A second prior art laser cutter is similar to that already described, except that the cutting table is moved around instead of the laser, which is kept stationary. In this case the cutting table is freely moveable along two mutually perpendicular axes so that any desired shape of garment may be cut. In such a cutter, the problems of moving the bulky laser and is overhead support frame are eliminated, but the cutting table is also very bulky and new problems are created when trying to move it around. In addition, the other drawbacks discussed with reference to the first prior art cutter, such as health and safety consideration and factory space, apply equally to this second cutter.
U.S. Pat. No. 5,200,592 combines elements of both the above prior art laser cutters. The fabric is cut on a cutting table the top surface of which is a belt conveyor. The fabric can be laid out flat on the cutting table directly from a roll. A stationary laser is used, but the focus point is moved over the flat laid-out fabric by a series of mirrors which move the focus point in two mutually perpendicular directions. A number of shapes are thus cut from the flat laid-out fabric and are than discharged into a bin by advancement of the belt conveyor which also draws new fabric from the roll to continue the cutting process. The cutting table of U.S. Pat. No. 5,200,592 is necessarily large, to permit cutting of garment-sized panels of fabric.